On Sun, Feb 12, 2017 at 04:36:19PM -0800, Dmitry Torokhov wrote:
> Many drivers create additional driver-specific device attributes when
> binding to the device and providing managed version of sysfs_create_group()
> will simplify unbinding and error handling in probe path for such drivers.
>
> Without managed version driver writers either have to mix manual and
> managed resources, which is prone to errors, or open-code this function by
> providing a wrapper to sysfs_create_group() and use it with
> devm_add_action() or devm_add_action_or_reset().
>
> Signed-off-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
> ---
Greg, gentle ping...
> fs/sysfs/group.c | 124
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/sysfs.h | 10 ++++
> 2 files changed, 134 insertions(+)
>
> diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
> index ac2de0ed69ad..24fc205fcb9b 100644
> --- a/fs/sysfs/group.c
> +++ b/fs/sysfs/group.c
> @@ -13,6 +13,7 @@
> #include <linux/kobject.h>
> #include <linux/module.h>
> #include <linux/dcache.h>
> +#include <linux/device.h>
> #include <linux/namei.h>
> #include <linux/err.h>
> #include "sysfs.h"
> @@ -409,3 +410,126 @@ int __compat_only_sysfs_link_entry_to_kobj(struct
> kobject *kobj,
> return IS_ERR(link) ? PTR_ERR(link) : 0;
> }
> EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);
> +
> +struct sysfs_group_devres {
> + const struct attribute_group *group;
> +};
> +
> +static int devm_sysfs_group_match(struct device *dev, void *res, void *data)
> +{
> + return ((struct sysfs_group_devres *)res)->group == data;
> +}
> +
> +static void devm_sysfs_group_remove_group(struct device *dev, void *res)
> +{
> + struct sysfs_group_devres *devres = res;
> + const struct attribute_group *group = devres->group;
> +
> + dev_dbg(dev, "%s: removing group %p\n", __func__, group);
> + sysfs_remove_group(&dev->kobj, group);
> +}
> +
> +/**
> + * devm_sysfs_create_group - given a device, create a managed attribute group
> + * @dev: The device to create the group for
> + * @grp: The attribute group to create
> + *
> + * This function creates a group for the first time. It will explicitly
> + * warn and error if any of the attribute files being created already exist.
> + *
> + * Returns 0 on success or error code on failure.
> + */
> +int devm_sysfs_create_group(struct device *dev,
> + const struct attribute_group *grp)
> +{
> + struct sysfs_group_devres *devres;
> + int error;
> +
> + devres = devres_alloc(devm_sysfs_group_remove_group,
> + sizeof(*devres), GFP_KERNEL);
> + if (!devres)
> + return -ENOMEM;
> +
> + error = sysfs_create_group(&dev->kobj, grp);
> + if (error) {
> + devres_free(devres);
> + return error;
> + }
> +
> + devres_add(dev, devres);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(devm_sysfs_create_group);
> +
> +/**
> + * devm_sysfs_create_groups - create a bunch of managed attribute groups
> + * @dev: The device to create the group for
> + * @groups: The attribute groups to create, NULL terminated
> + *
> + * This function creates a bunch of managed attribute groups. If an error
> + * occurs when creating a group, all previously created groups will be
> + * removed, unwinding everything back to the original state when this
> + * function was called. It will explicitly warn and error if any of the
> + * attribute files being created already exist.
> + *
> + * Returns 0 on success or error code from sysfs_create_group on failure.
> + */
> +int devm_sysfs_create_groups(struct device *dev,
> + const struct attribute_group **groups)
> +{
> + int error;
> + int i;
> +
> + if (!groups)
> + return 0;
> +
> + for (i = 0; groups[i]; i++) {
> + error = devm_sysfs_create_group(dev, groups[i]);
> + if (error) {
> + while (--i >= 0)
> + devm_sysfs_remove_group(dev, groups[i]);
> + return error;
> + }
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(devm_sysfs_create_groups);
> +
> +/**
> + * devm_sysfs_remove_group: remove a managed group from a device
> + * @dev: device to remove the group from
> + * @grp: group to remove
> + *
> + * This function removes a group of attributes from a device. The attributes
> + * previously have to have been created for this group, otherwise it will
> fail.
> + */
> +void devm_sysfs_remove_group(struct device *dev,
> + const struct attribute_group *grp)
> +{
> + WARN_ON(devres_release(dev, devm_sysfs_group_remove_group,
> + devm_sysfs_group_match,
> + /* cast away const */ (void *)grp));
> +}
> +EXPORT_SYMBOL_GPL(devm_sysfs_remove_group);
> +
> +/**
> + * devm_sysfs_remove_groups - remove a list of managed groups
> + *
> + * @dev: The device for the groups to be removed from
> + * @groups: NULL terminated list of groups to be removed
> + *
> + * If groups is not NULL, remove the specified groups from the device.
> + */
> +void devm_sysfs_remove_groups(struct device *dev,
> + const struct attribute_group **groups)
> +{
> + int i;
> +
> + if (!groups)
> + return;
> +
> + for (i = 0; groups[i]; i++)
> + devm_sysfs_remove_group(dev, groups[i]);
> +}
> +EXPORT_SYMBOL_GPL(devm_sysfs_remove_groups);
> diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> index c6f0f0d0e17e..d9a5b8aab0e2 100644
> --- a/include/linux/sysfs.h
> +++ b/include/linux/sysfs.h
> @@ -282,6 +282,16 @@ int __compat_only_sysfs_link_entry_to_kobj(struct
> kobject *kobj,
> struct kobject *target_kobj,
> const char *target_name);
>
> +struct device;
> +int __must_check devm_sysfs_create_group(struct device *dev,
> + const struct attribute_group *grp);
> +int __must_check devm_sysfs_create_groups(struct device *dev,
> + const struct attribute_group **groups);
> +void devm_sysfs_remove_group(struct device *dev,
> + const struct attribute_group *grp);
> +void devm_sysfs_remove_groups(struct device *dev,
> + const struct attribute_group **groups);
> +
> void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr);
>
> int __must_check sysfs_init(void);
> --
> 2.11.0.483.g087da7b7c-goog
>
--
Dmitry
